Conventional anchors used in oil wells for supporting pumps or the like within the well casing incorporate a tubular anchor frame, a slip cage secured to the frame and a plurality of slips having cam and follower surfaces or conical surfaces, the slips actuable by appropriate mechanisms to force them outwardly into anchoring position by engagement with the walls of the casing. That actuation is generally accomplished by a rotary action on the drill string above the anchor frame, to which the anchor frame is attached, which rotary action causes a drive means to operate the anchor slips. In Canadian Patent No. 2,077,990, of Jani et al. issued Nov. 21, 1995, that action is accomplished by means of rotation of a mandrel associated with the anchor, in one direction, so as to cause movement of drive cones into position beneath the slips, forcing the slips outwardly into anchoring position against the casing walls. Rotation of the mandrel in the other direction moves the drive cones away from position beneath the slips to free the slips from anchoring engagement on the casing walls.
Another reference of general background interest to the present invention is Canadian Patent No. 1,274,470 of Webber issued Sep. 25, 1990 which teaches an oil pumping apparatus incorporating a rotary pump on a production tubing string, in the form of a rotary pump having a stator and screw type rotor, with a no turn tool secured to the stator to prevent right-hand rotation of the stator while permitting vertical movement of a stationary means associated with the stator. Other references of general background interest include U.S. Pat. No. 2,737,245 issued Mar. 6, 1956 of Knox, U.S. Pat. No. 3,102,592 issued Sep. 3, 1963 of Dollison, U.S. Pat. No. 3,887,006 issued Jun. 3, 1975 of Pitts, Canadian Patent No. 371,318 issued Jan. 18, 1938 of Clark, Canadian Patent Application No. 2,162,409 published May 9, 1997 of Jani and Canadian Patent Application No. 2,188,175 published May 9, 1997 to Jani. These latter two Jani references teach convex wedge-like surfaces supported on the mandrel rotatable into position beneath the drag slips and to cause the slips to move outwardly into set position.